![\"\"](\"http://www.mathskey.com/userfiles/image/steps_images/step1.JPG\")
Method 1:
\List the factors of each number.
\Factors of 54: 2, 3, 6, 9, 18, 27, 54.
\Factors of 63: 3, 7, 9, 21, 63.
\Identify the greatest common factor.
\The greatest common factor of 54 and 63 is 9.![\"\"](\"http://www.mathskey.com/userfiles/image/steps_images/step2.JPG\")
Method 2:
\Write the prime factorization of each number.
\54 = 6 × 9.
\63 = 7 × 9.
\The GCF is the product of the common prime factors in each number.
\GCF = 9.
\The greatest common factor of 54 and 63 is 9.![\"\"](\"http://www.mathskey.com/userfiles/image/steps_images/solution.JPG\")
The greatest common factor of 54 and 63 is 9.